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Update on FMS Repair

Stephen TrentalangeSTAR Management Meeting

October 31, 2014

FMS Repair Work Summary• Restacking work nearly completed– Small Cells: 100% complete (476/476)– Large Cells: 95% complete (748/788)– External cabling 100% complete

• Running with DAQ: LED/Jet Patch trigger to diagnose problems with HV and signals

• Cable mapping so far is correct for HV/signals• Large cells: various problems ~24/572 channels• Small cells: HV problem: +6V power supply;

working with the electronics techs to diagnose.

Previous Problems:Updated• 216 Large Cells Left to complete– 34 old FMS Cells (216-34=182)– 90 from PSU by Nov 2 (182-90=92)– 12 bases available (92-12=80 still at PSU)

• Need 5 magnetic shields• Cabling/Stacking 1 week work• Noticed cracking in single small

cell/north side: seems stable

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Cosmic Rays Observed

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LED Signal

LED IssuesNo Signal

Yale Bases

Russian Bases

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Conclusions• Training of 2 extra on site experts in operation/ hardware for

FMS: Sam Heppelman/Grant Webb• Schedule for repair work on bases at PSU is tight, but a stream

of bases is arriving at BNL. Installation is not difficult.• Repair work on individual channels remains before run.• November-January Tasks:

– Repair work on individual channels– Small cell HV (+6V supply)– Spares for HV/LED control machines in hall– Spares for CW low voltage power supplies

• Work on “runaway trigger” problem with Jack/Chris/Eleanor

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Stacking the FMS

The South Side is Fully Stacked

The North Side is 90% Stacked

Need the remaining 150 PMT bases from PSU.

Survey of FMS location completed

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The Forward Meson Spectrometer1264 Pb-glass cells

788 large cells 476 small cells